Great little plug-in! I haven't had any issues with it crashing Safari, and it's one of those little tools that's just so handy to have when you need it.
I love that it puts the original link into a downloaded file's Get Info comment as well -- very nice. It would be nice to see that info in the main iPlace window somewhere as well (maybe with a copy-to-clipboard option), but at least it's available somewhere.
The only other thing this needs is a quick way to reveal the downloaded files in the Finder. But otherwise, it does what it says and stays out of the way. Nice tool.